1. Technical Field
The present invention relates to a method of leaching copper and gold from sulfide ores.
2. Related Art
In recent years, a technique of recovering copper from sulfide ores by the wet process has been attracting attention, as a substitute for the conventional dry process. While the content is very small, the sulfide ores often contain additional noble metals such as gold, so that there is a need for economically recover not only copper but also such noble metals.
Known techniques of coping with the problem is such as subjecting the residue, remained after copper leaching, to gold leaching, using chloride and bromide of alkali metal or alkali earth metal, and chloride and bromide of copper and iron (Japanese Laid-Open Patent Publication No. 2009-235519). According to the description, the method successfully leaches and recovers copper and gold contained in copper sulfide ores at high leach rates, merely by making use of air, but without using any special oxidizing agent.
Another known method is such as subjecting the residue, remained after copper leaching, to gold leaching after the copper content in the residue is decreased to 7.9% or below, based on the knowledge that gold starts to leach after the copper content in the residue is decreased to 7.9 or below (Japanese Laid-Open Patent Publication No. 2009-235525).